Stucco is a cement mixture used for siding, mostly known to be found on Mission or Spanish Style homes.  The cement is combined with water and inert materials, such as sand and lime.  Usually, wooden walls are covered with tar paper and chicken wire or other type of metal screening in order to give the stucco "something to grab to".  Once a stable framework is in place, it is covered with the stucco mixture.  Sometime, the cement mixture is applied directly to specially prepared masonry surfaces.

Although stucco-sided homes became popular in twentieth century America, the concept of using cement mixtures in architecture goes back to ancient times.  Wall frescoes by ancient Greeks and Romans were painted on fine-grained hard plaster surfaces made of gypsum, marble dust, and glue.  Stucco techniques were elaborated by the Italians during the Renaissance and spread through Europe.  This marble dust compound could be molded into decorative shapes, polished to a sheen, and/or painted.

Many homes built after the 1950's use a variety of synthetic materials which resemble stucco.  Mock stucco siding is often composed of foam insulation board or cement panels secured to the walls.  Although synthetic stucco may look authentic, real stucco tends to be heavier.  Walls made of genuine stucco sound solid when tapped and will be less likely to suffer damage from a hard blow.  Also, genuine stucco holds up well in wet conditions.  Although it is porous and will absorb moisture, it will dry easily without exposing the structure to damage.  The most common stucco construction in this area is the Traditional Hardcoat method.  EIFS (Exterior Insulation and Finish System), another form of stucco construction, has often been the target of moisture problems.  The underlying wood in EIFS sided homes have been known to suffer from moisture and rot damage.  As always, whether building, repairing, and buying a stucco-sided home, it's always best to have a professional inspect your stucco and structure.

Traditional Hardcoat
Traditional hardcoat stucco, most commonly used in today's stucco market, is a hard cement-like cladding applied to the exterior of a home.  Hard coat systems can utilize an insulator board, but always are required to have a horizontally lapped moisture barrier (typically felt paper) between the stucco and the structural materials.  There is also a requirement for horizontal and vertical control joints to minimize cracking.  Due to its hardness, it is subject to excessive cracking when proper installation features are not present.  To protect against moisture, a "weep screed" is required at the junction of the framing and the foundation to allow moisture to escape into the atmosphere.

EIFS (Exterior Insulation and Finish System)
EIFS was developed in post World War II Germany to repair damage done during the war.  The product was introduced into the United States primarily for commercial applications and later introduced into the residential marketplace around 1980.  EIFS utilizes an insulator board as part of the layering process and address tremendous insulation capability to the home versus other siding and cladding systems.  When installation is not followed properly, the system continually breaks caulk seals and cracks allowing moisture to enter and affect the structural materials to which it's applied.  Unlike other claddings, EIFS is adhesively, and sometimes, mechanically attached directly to the sheathing or other structural members, causing moisture to be trapped and eventually rotting.

Below are some features for using stucco: